The merge strategy is no longer set globally as it was in previous versions of Hiera, and this is a big improvement. The valid merge strategies are as follows:
- first: A retrieval of the first match is made; this is equivalent to the traditional hiera() default behavior
- unique: This is an array merge, equivalent to the old hiera_array() function
- hash: This is equivalent to the old hiera_hash() function without deep merging enabled
- deep: This is equivalent to the old hiera_hash() function with deeper merging enabled (deep is no longer supported)
Check the official Hiera 3.3 documentation to understand the concept of deep and deeper merges fully: https://puppet.com/docs/hiera/3.3/lookup_types.html#example. Note, deeper merges in Hiera 3 are equivalent to a deep merge in Hiera 4+.
deep merges are no longer supported.
deep merges are no longer supported.